Oil vapor filter



Jan. 24, 1939. F. KRA|SSL,-JR

OIL VAPOR FILTER Filed Oct. 13, 1936 m H w L 5 m mm d K mm m F ATTOR N EYS Patented Jan. 24, 1939 UNITED STATES PATENT OFFICE 011. VAPOR FILTER Frederick Kraissl, Jr., Hackcnsack, N. J. Application October 13, 1936, Serial No. 105,426

6 Claims.

This invention relates to improvements in oil vapor 'filters, and has for a main object the elimination of smoke formed by disintegration and dispension of lubricant in the air gas discharged from such machines.

' The smoke consists of oil or lubricant broken up into minute dropletshaving a very small specific surface and great stability. In fact, the

' smaller these droplets are, the greater their stability;

- A further object of the invention is the provision of, means, through which the discharged air or gas passes, adapted to force coalescence of these droplets or minute particles of oil. The

is tiny droplets or particles of oil may be electrically charged and of the same sign, therefore repellent to each other.

Another object of the invention is the provision of means for forcing said particles into fit coalescence in spite of said charge.

Other objects and advantages of the invention will be apparent to those skilled in the art.

In high speed compression or vacuum machines of the prior-art, the discharged gas or air carries 25 lubricant, in an entrained, atomized colloidal or gaseous state. Air or gasso laden was found to be unsatisfactory and unsuitable for many purposes. According to the present invention, this finely divided lubricant is separated from the 30 discharged air or gas and is returned to a lubricant reservoir, so that it may be used over again for lubricating purposes.

The dispersion of lubricant in the air or gas discharged from the compressor or pump is due 85 to sudden and violent collision between the surface of the lubricant within the compressor, and the solid substance, such as the rotor and the moving parts of the pump. This is particularly true in vacuum pumps. This causes the specific surface of the lubricant to extend beyond the limits of its surface tension, with the result that it becomes unstable and breaks up into minute droplets having a smaller specific surface and 45 greater stability. It has been found that the smaller the minute droplets become, the greater their stability becomes. 7 It has also been found that due to friction with the dispersing medium,-the moving parts 53 in the compressor,these minute particles of lubricant appear to be electrically charged.

It has also been found that the dispersion is aided by high temperatures; therefore, as the machine heats up, the dispersion increases. The

electrically charged minute particles are very stable due to the fact that they all carry light electrical charges and repel each other.

In this application, the minute particles of lubricant forming smoke in the discharge of air or gas will be termed aerosols, which may be taken to mean smoke formed by disintegration and dispersion of liquid or solid in gas or air.

The elimination of the aerosols from the discharged air or gas may be efiected by the following:

(1) Promoting coalescence by the presence of dust or grease at the surface of impact.

(2) Forced coalescence of the particles.

(3) Electrical precipitation.

In high speed compression and vacuum pumps, particularly in those of the rotary type employing vanes, rollers and the like, the presence of smoke in the discharged air or gas has been a problem with the manufacturers, and in order to obtain discharged air which was satisfactory (not containing suificient smoke to interfere with the intended use), many of the manufacturers have reduced the speeds of the compressors with the following results: I

(1) The compressors to operate at a lower speed 6 and still deliver the same quantity of air, had to be increased in size.

(2) Expensive reduction gears were necessary between the motor and the compressor to obtain the necessary reduction in speed.

(3) Such gearing had to have attention and frequent oiling.

herein described apparatus and method of elimihating the smoke was devised.

Referring to the drawing: I s Figure 1 is a sectional elevation of one form of aerosol separator;

Figure 2 is a transverse sectional view of the device shown in Figure 1, taken along the line 2-2 thereof;

Figure 3 is a' transverse sectional view of the *5 device shown in Figure 1, taken along the line 33 thereof;

Figure 4 is a sectional view of the device shown in Figure 1, taken along the line H: and Figure 5 is an enlarged sectional view showmg the path taken by the smoke-laden air as it is discharged into the new and improved separator. I

In high speed-compression and vacuum pumps, particularly those of the rotary type employing 66 vanes, rollers and the like, the discharged air or gas which is laden with lubricant may be passed through a chamber or the base of the compressor and impacted against a body of lubricant or the walls of the chamber and thereby separate therefrom a. large percentage of the heavier particles of oil. The discharged air or gas which is still laden with minute particles of oil in the form of smoke, may then pass into a separator such as that shown in Figure 1, via the pipe 5| of the base. A pipe 5i has its lower end secured to a flange 52 which may be welded or otherwise secured to the surface 24.

The body portion 53 of the new improved separator has formed therein a chamber 54 and a second chamber or sump 55. The pipe 5| connects to the lower end of the chamber 54. A stand pipe I29 is threaded into the body 53 and extends into the chamber 54. The upper end of the stand pipe I29 is closed and a series of small holes I3I is formed in the wall of the stand pipe communicating with the interior thereof. This may be seen in Figure 1, and the enlarged view in Figure 5 shows the preferred angular relation between the hole I3I and the surface of the inner wall of the cylinder housing 69.

Smoke laden air or gas passing via the pipe 5I, the chamber 54, and the stand pipe I29, strikes the inner wall of the cylindrical housing 69 at an angle, as indicated by the arrow in Figure 11, and therefore with a, rotary impact. This causes the heavier particles of oil which had not been removed from the air, prior to its entrance into the stand-pipe I29, to trickle down the walls of the cylindrical housing 60. The cylindrical housing may be made of glass so that this action may be watched.

The upper face of the body portion 53 has a recess 59 formed therein into which the cylindrical housing fits both in oil-tight and air-tight relation, as will presently be described.

The surface of the bottom of the recess 59 slants gradually down-that is, helically. The surface at the point 6| being highest, at the point 62 intermediate, and at the point 63 lowest, so that all of the oil separated by the rotary impact above described will drain down and around to the point 63. At this point a drain pipe 84 communicating with the surface in the immediate neighborhood of the point 93 extends downwardly through the chamber 54 to deliver drained oil to any desired point. It will be noted that the stand pipe I29 and the drain pipe .94 are not in line with each'other. The drain pipe 94 is spaced apart from the stand pipe 56,

as is clearly shown in Figure 3.

The recess 59 has an upstanding boss 65 formed in the center thereof integral with the body portion 53. A passage 99 communicating with the sump 55 terminates in the boss 65 and has a threaded hole 61 therein.

A boss 98 formed in the side wall of the body portion 59 has a, threaded hole 69 formed therein, terminating in a passage III which also communicates with the sump 55 and forms an outlet for the air after the aerosols have been separated therefrom.v A web II serves to extend the passage to a. point below the level of the passage I9. A boss I2, formed on the lower wall of the body member 53, has a tapped end hole I3 communicating with the sump 55 at its lowest point to which a suitable drain pipe may be connected. V

A top closure plate 89 having a recess 99 cylindrical housing 69 and is provided with ears, not shown in Figure 1 but lining up with ears 94 and 95' shown in Figures 2 and 3. Bolts 93 pass through holes in these ears and engage tapped holes in the ears 94 and 95 formed integral with the body portion 53 for tightly securing the cylindrical housing in air-tight and oiltight relation to the recesses 59 and 99. To further insure proper sealing, a suitable oil resistant varnish or liquid, or a suitable gasket, may be applied to each end of the cylindrical housing member 69 and to the surfaces adjacent thereto before the body portion, the housing, and the top closure plate are assembled. If desired, the ears 94 and 95 need not be tapped, but instead thebolts 93 may be tightened up by means of nuts. A plug I99 is provided in the top closure plate.

After the heavier particles of oil in the discharged air or gas are separated, due to the helical or spiral motion given to the air entering the cylindrical housing 69 (which may be considered the first stage of the oil separation), the smokeladen air is then subjected to a second stage in the process of separation which consists in passing it through a medium to cause the agglomeration of the lubricant particles into retainable liquid lubricant.

It has been found that by passing the smokeladen discharged air or gas through a porous or semi-porous medium so constructed that it will effect the agglomeration of the lubricant particles, both when saturated with lubricant or when unsaturated, and do so without any impractical back pressure.

It has been found that certain flbrous materials, particularly kapok, or other cotton and vegetable fabrics may be used to cause the minute particles of oil to coalesce. Excellent results have also been obtained in the use of combinations of fibrous materials and porous mediums.

The threaded boss 65 is provided with a nipple II 9, which in turn supports a flanged member III. The flanged member has fltted thereto, in fluid-tight relation, a cylinder H2. The upper surface of the flanged member is cut by a conical hole I I9, leaving a flat annular surface I I4 which forms a support for the elements of the fllter.

A cartridge comprised of an annular ring H5, a lower screen disk I I9, and an upper screen disk I", with a mass of steel wool II 8 therebetween, forms an infiltrate.

A mass of kapok I I 9 rests upon the screen disk I I1 after which a screen disk I29 is applied. It

will be noted that the disk I29 is cuppedthat is to say, concave, when viewed from the top-so that when pressure is applied thereto, as will presently be described, the material II9 will be forced against the walls of the cylinder II2 to form therewith a packing lock.

The kapok is applied in the dry state so that the small particles of oil in the first smoke-laden formed therein is fitted to the upper end of the therethrough without coalescence.

After the kapok becomes impregnated, it immediately starts causing the oil to coalesce; agglomerated oil may pass from the surface of the screen disk I I1 and via the steel wool 8 to the screen H6. From the latter, the oil may fall into the conical space H3 and pass via the passage 65 into the sump, 55.

I have substituted other fibrous materials, both animal and vegetable, for the kapok, but have found that of all the fibrous materials tested, many gave satisfactory results but kapok is the most efilcient for'the purpose. In order to prevent perforations in the screen ,1 from becoming clogged, I employ a thin layer of steel wool or the like along the upper surface of thescreen II! as indicated by the numeral H8, and I have also found it desirable to apply a thin layer of steel wool or the like between the lower face 'of the screen I20 and the fibrous material H9.

A yoke l2l has one leg I22 extending down one side of the cylinder 2 and is secured to the flanged member I I I by means of a screw I23 passing through the wall of the cylinder. The other leg I24 of the yoke passes down along the opposite side of the cylinder and is secured to the flanged member by means of another screw I23". A pressure screw I25, having its end seated in an annular boss member I26, is provided for reguquantity paths.

lating the tension of a spring I21 against the spring disk I20 through the medium of the locating boss I28.

The air or gas is given a rotary or spiral motion as it enters the chamber 59, and while in said rotary motion passes into the upper portion I38 of the chamber thereby causing the heavier particles of oil to impinge upon the interior walls of the cylinder 68. This oil trickles down and is drained out via the pipe 64. The smoke-laden air then passes through the screen I20, the fibrous material N9, the screen II I, the steel wool H8, and the screen H6; and then, freed from Oil, passes via the passage 66 to the oil sump 55. Due to the fact that the medium H9 is horizontally positioned in the cylinder, all of the agglomerated oil must pass therethrough and via the passage 66 into the sump 55.

The term permeable, hereinafter used in the claims, may be taken to mean any material, whether of a fibrous nature or of a mineral nature and having such porosity and (such) arrangement of grain that, after becoming impregnated with minute particles 'of liquid forming a smoke in air or gas, it has the property of forcing subsequent minute particles of liquid, forming said smoke, into coalescence, upon, the passage of such gas therethrough, thereby forming larger particles of liquid incapable of suspension in said air or gas without appreciable or impractical back pressure; this property being further facilitated by the cohesion between the impregnation and the subsequent particles of liquid.

Another arrangement contemplates connecting devices such as shown in Figure 1 in parallel or multiple so that the plurality would dividethe quantity of air or gas-into a plurality of smaller By this arrangement, the rate of separation for each individual device is 'cut down with the advantage that the liquid may drain from the semi-permeable material fast enough to prevent the latter from becoming clogged.

I do not limit myself to mounting the device on the base or oil reservoir of a compressor but instead some arrangements contemplate the the compressor or the oil reservoir and delivering the smoke or aerosol laden air or gas to the device by piping or any other suitable means, in which'case the separated liquid passing out via the drain pipes 64, or the liquid drained from the sump 55, may be collected, piped to any desired point, or allowed to go to waste in accordance with which is most desirable.

It is obvious that other modifications of the method of removing smoke or aerosols from the discharged air or gas may be made by those skilled in the art without departing from the spirit of the invention as defined in the following claims.

What is claimed is:

l. A device for removing minute particles of liquid from a gaseous medium comprising, a circular chamber, a drain pipe communicating therewith, means to deliver said medium to said chamber with a rotary motion w lel b i gheavier of said particles gather on the walls of the chamber by impact and drain down said walls and out through said drain pipe, a second "chamber spaced apart from said first chamber, means forming a passage between said chambers, an outlet port for said gaseous medium formed in said second chamber, a flanged member secured to said boss and having formed therein a hollow portion communicating with said passage, a cy-' of porosity and arrangement of grain that agreater percentage of said particles is separated from said gas by forced coalescence, and means for removing coalesced liquid from said second chamber.

2. In a device for separating minute particles of liquid from gases, in combination, a body member having an inlet passage and a sump formed I therein, a wall between said passage and said sump, a discharge passage communicating with said sump, a boss in the upper surface of said body, a conduit leading to said sump through said boss, a closure member mounted in fluidtight relation to the topofsaidbody'and forming a chamber, a stand-pipe in said chamber communicating with said inlet passage and having a discharge hole angular with respect to the wall of said closure member adapted to give smokeladen air entering said chamber a rotary motion, whereby heavier particles of liquid may impinge upon the walls of the closure member and drain down to the bottom of said chamber, a drain pipe communicating with the bottom of said chamber for draining off the heavier particles of liquid as they are separated, a cylindrical member supported by said boss and having its upper end communicating with said chamber and its lower end in communication with said sump through said conduit, a pair of perforate disks mounted in said cylindrical member, a mass of permeable material positioned between said disks, adjustable means for applying tension to said material through one of said disks to maintain said material in sealing relation to the walls of said cylindrical member, said material together chamber and said sump through which said mounting of the device separate and apart from smoke-laden gas must pass to leave said chamber. 7

whereby the particles forming said smoke are forced in coalescence and drained into said sump permitting the clean air or gas to pass out through said discharge passage, and a second drain pipe for draining said sump.

3. In a device for separating minute particles of liquid from gases, in combination, a body member having an inlet passage and a sump formed therein, a wall between said passage and said sump, a dischargepassage communicating with said sump, a boss in the upper surface of said body, aconduit leading to said sump through said boss, a closure member mounted in fluidtight relation to the top of said body and forming a chamber, a stand-pipe in said chamber communicating with said inlet passage and having a discharge hole angular with respect to the wall of said closure member adapted to give smokeladen air entering said chamber a rotary motion, whereby heavier particles of liquid may impinge upon the walls of the closure member and drain down to the bottom of said chamber, a drain pipe communicating with the bottom of said chamber for draining oil the heavier particles of liquid as they are separated, a cylindrical member supported by said boss and having its upper end communicating with said chamber and its lower end in communication with said sump through said conduit, a plurality of perforated supports mounted in said cylindrical member and forming a permeable partition between said chambers, a mass 0! material between two adjacent perforated supports forming an infiltrate, a mass 01 permeable material positioned between others of said members and having such a degree of porosity and arrangement of grain that the greater percentage of said particles is separated from said gas by forced coalescence when the latter is passed therethrough, adjustable means for applying tension to said semi-permeable material through at least one of said disks to maintain said semi-permeable material in sealing relation to the walls of said cylindrical member, said materials together with said disks forming a partition between said chamber and said sump through which said smoke-laden gas must pass to leave said chamber, and means for draining coalesced Iii aid from said sump.

V A, A device for removing liquid particles from a gaseous medium comprising a chamber, means to deliver said medium and to impart a rotary motion thereto, whereby the heavier of said particles may impinge upon and drain down the walls of saidchamber, a drain pipe communicating with said chamber at a low point therein for leading said drained liquid from said chamc,144,ce1

ber, means defining a sump in another portion of said chamber, an outlet port, a second drain pipe communicating with said sump, and a cartridge comprised of two adjacent perforated supports with kapok therebetween and forming a barrier between said chamber and said sump, the pores of said kapok in said cartridge after becoming impregnated with said liquid being adapted to force succeeding liquid particles into coalescence whereby the coalesced liquid may drain into said sump and out through said second drain pipe. i

5. A device for removing minute particles of liquid from a gaseous medium comprising, a circular chamber, a drain .pipe communicating therewith, means to deliver said medium to said chamber with a rotary motion whereby the heavier of said particles gather on the walls of the chamber by impact and drain down said walls and out through said drain pipe, 9. second chamber spaced apart from said first chamber, means forming a. passage between said chambers, an outlet port for said gaseous medium formed in said secondichamber, a flanged member secured to said boss and having formed therein a hollow portion communicating with said passage, a cylindrical member secured to said flanged memher and having its upper portion in communication with said first chamber, a plurality of perforated supports mounted in said cylindrical member forming a permeable partition between said chambers, a mass of material between two adjacent perforated supports forming an inflitrate, a mass of kapok positioned between others of said members, said kapok having such a degree of porosity and arrangement of grain that a greater percentageof said particles 'is separated from said gas by forced coalescence, and means for removing coalesced liquid from said 'second chamber.

therethrough being adapted to force succeeding liquid particles into coalescence, whereby the coalesced liquid may settle into said sump and may pass out through said draining means.

FREDERICK KRAISSL, Ja. 

